Balast resistor or no?

Newsflash!
Coils WILL get hot at idle with points & the Ch ECU. That is because:
- neither has dwell control
- dwell is extended to prevent high speed misfires
- but this means because the dwell is fixed, there is more dwell period at idle where it is not needed
- so the coil heats up at idle because it is switched 'on' longer than it needs to be

One of the benefits of GMs HEI is variable dwell, which is reduced at idle to reduce coil heating.